I live on 5 acres of very fertile farm land/pasture in the Bullsbrook hills and I am interested in permaculture and self sustainability. Although I am very happy with the quality of the soil on my block unfortunately I must rely on rain as my only source of water, meaning that water is a very finite and valuable resource to me, currently I can hold ~ 330,000 litres max and although this sounds like a lot I have big plans for food production. On discussing this with the parents of one of my daughter's friends they told me about aquaponics and how it only required ~ 10% of the water as traditional dirt farming and I was hooked on the idea of growing vegetables using recycling water with the bonus of fish to eat. This was a year and a half ago, and after seeing my new friend's system a few months ago I put my plans into action.

I bought a 3,500 L round fibreglass tank that leaked of an old Italian bloke who used to raise marron for $200 and patched the leaks, I friend who owns an irrigation chain was able to supply me with a Grunfos sump pump with a float switch and while I was in his shop he found out that his supplier of expanded clay was offering a one off 20% discount on bulk orders of 45L bags (55 to the pallet Canna brand) so I picked them up for $24 a bag which was substantially cheaper than the original trade price he was going to supply them for.I have two 1800 X 400 round aqua lined corrugated iron grow beds from Rainfill Tanks .

My system is a CHFT PIST set up with a T piece overflow gravity feeding water to my grow beds. Initially I am only going to stick with the 2000L of grow beds I have ordered but plan to expand the system out to a 2:1 ratio using more of the 1000L tank grow beds and some half blue barrels to grow more permanent plants like fruiting trees and bushes. The beds will be flood and drain using slow drain standpipes initially and once I get the hang of it I will play around with some loop syphons. I am going to try goldfish and if I can keep them alive I will move on to silver perch, I may also try marron as I have a free supply of mature adults, this would only be a hobby to see if I can get them to breed as I think marron meat is completely over rated and I will only eat it if it is free. I think I will use a 1000L IBC as a sump with the system being float activated.

I finally got my system working properly today after about 5 days buildling and construction and 3 days straight trying to get the freakin bell syphons to work and now she runs like a charm, I may still have some fine turing to do, I will see in the morning if it is still running well.

Here are some picture of the details of my set up. First the freakin bell syphon with a side outlet to fit the drainage supplied with the growbeds.

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Here is my "V" water trap, I intially used a "U" made of 25mm elbows but I found the pressure needed to trigger the syphon was too geat and my bells were getting smaller and smaller to try and prevent the beds over flowing and I started to develope bell envy. Now my bell is a "good size" as my wife puts it and I have more confidence.

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The first gravel guard I made had round holes in it but I found that with the variable size of the expanded clay one or two would always get in a block the system so I cut the verticle hole seen below with and angle grinder to prevent this. I also cut my leg in the process and required 4 stiches so I have my first aquaponics scar.

Are the growbeds / tanks aqualined however? The zinc leaches out and poisens the fish otherwise.

The tanks come aqualined form the rainfill tanks factory, they are specifically sold a aquaponics growbeds. I was put on to them by aquaponicists down the hill who I believe were some of BYAP's first customers before they started with there own systems and are what were recomendeed to them. The down side to them is that when on stands with the round shape it is hard to reach the middle.

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Also, you may have problems with stuff building up in the big fish tank, a small overflow like that probably wont lift enough crap from the tank.

Can you give me more advice in this area? I am currently using 40mm pipe for the overflow because that is what fitted the existing drainage in the FT. What size should I use? I would think that a larger pipe with the same volume of flow (rate controlled by taps to suit the needs of the bell siphon) whould produce less suction and therefore remove less waste. Would bigger crenulations be a better way of ensuring more or bigger waste is removed? I have no idea how much or what type of waste will build up as I am new to fish.

Picture of my sump, Grunfos 8000l/hour float activated pump, non return valve on pipe which easily gets held open by gravel resulting in accidental siphon of my FT, may have to re-think design. Sump only ~400 litres for now which is enough for the system to run well but I will lose a lot of water if the power fails as it will over flow. I am going to replace with a 1000L IBC and use the current sump with small growbed over the top as a stand alone system to be used as a quarantine tank.

Joined: Jun 12th, '09, 18:14Posts: 127Gender:Are you human?: Last time I looked
Location: Western Australia

Congratulations looks like a great system you have there Simo. Welcome to the ever expanding world of aquaponics I looked into those round grow beds myself but was put off by the reach to the middle but where there is a will there is a way.Good luck with it and we will look forward to the progress photos. Everyone loves photos

I am currently using 40mm pipe for the overflow because that is what fitted the existing drainage in the FT. What size should I use? I would think that a larger pipe with the same volume of flow (rate controlled by taps to suit the needs of the bell siphon) whould produce less suction and therefore remove less waste. Would bigger crenulations be a better way of ensuring more or bigger waste is removed? I have no idea how much or what type of waste will build up as I am new to fish.

I would have though that 40mm pipe under gravity flow alone would not cope with the full 8000 lph of your pump, but anyway, you will need to ensure that the water in your big tank gets a decent swirl happening to keep all the crap suspended in the water, allowing it to flow out the overflow.

I see, the pump pipe is also 40mm; it is activated on a float switch so it quickly tops up the FT when the sump becomes full and the FT slowly drains over time into the growbeds. The rate of drain is governed by taps on each bed to ensure the bell siphons work properly. The return pipe form the pump has a venturi air intake and ends underwater half way down the FT at an angle so that when the pump is running a circular current is created that causes all solid waste to be pushed to the centre of the tank where the up take is hopefully gets removed.

I picked up an air pump with battery back up, water test kit and thermometer from the BYAP shop today and I was talked into cycling with fish instead of pee pee, so tomorrow I will pick up 50 silver perch fingerlings for the Gidgie fish farm. I only want a small number to start as I have a small grow bed volume in comparison to the tank. They are a bit smaller than I would have liked (30 to 50mm) but they are all I could get at short notice and I want to get started on cycling the system asap.

When I first attch my bell siphons they work perfectly for the first cycle, they kick in fairly hard and fast at just the right GB water hieght and drain full bore and cut out completely. The next time they cycle they start to weakly siphon at the rate that the bed is filling or just slightly slower when the GB water height is 1/4 of the hieght the siphon started on the frist cycle, which is well below the height of the inner standpipe.

Obviosly this makes it hard for the bell to reach siphon pressures and it all becomes unreliable.

I think I know the reason and will try to fix tomorrow but I would like some advice form more experienced aquaponicists. My theory is that my air break tube is too small and once it breaks the siphon the water remaining in the tube due to water tension is preventing the water in the bell draining back down by not allowing the air back in. When I start the second flood/drain cycle the bell is half full already therefore contains less air then the first cycle and requires less pressure to start draining (hence the premature leakage) and the air volume is out of sync with the water trap volume so does not fully siphon rather just dribbles over the stand pipe.

I am using 4mm flexible pipe but the inlet into the bell is a small irrigation elbow with an internal diameter of less than 2mm, the end of the tubing is about 10mm above the top of my crenulations

What size pipe should I use for the siphon air break tube?

Does anyone know where I could get a bigger elbow fitting for the top of the bell?

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